SailNet Community

SailNet Community (
-   Gear & Maintenance (
-   -   Fresh water flush Yanmar diesel (

bgotbaum 07-21-2003 08:30 AM

Fresh water flush Yanmar diesel
Can anyone tell me how to fresh water flush my 1985 G3 27hp Yanmar diesel. It''s not circulating enough water to keep the engine from overheating.

I have cleared the raw water intakes on my saildrive, checked the pump hose to make sure its clear, pulled the water pump and inspected the impellar and looked for debris, and the water still trickles out.

The only other thing i can think of is buildup in the engine.

Any and all thoughts welcome.

Thank You, GG (Charleston, SC)

knothead 07-21-2003 03:04 PM

Fresh water flush Yanmar diesel
I''m a rigger, not a mechanic so I don''t claim to know what I''m talking about but a few years ago I installed a y-valve on my salt water intake just after the strainer and connected a hose which I ran into the bilge. I have a 10 hp salt water cooled Yanmar and what I did was partially fill the bilge with fresh water before I went out and then suck it back out with the engine when I got back to the dock. I figured it couldn''t hurt to have fresh water sitting in the engine between sailing trips rather than salt water. The bilge was kept clean that way too. Like I say, there may well be a valid reason why this is not a good idea or doesn’t help anyway, and I would be interested to hear others thoughts.

knothead 07-21-2003 03:06 PM

Fresh water flush Yanmar diesel
Actually, I wonder what would happen if I sucked some vinegar into the engine and let it sit for a few days.

ssmith8523 07-24-2003 12:20 PM

Fresh water flush Yanmar diesel
I suspect your heat exchangers on perhaps both the fresh and raw water sides need to be de-scaled, especially if zincs have not been maintained. You can remove them and have them descaled in an acid bath. I had an overheating problem with my 25hp Westerbeke, and the mechanic pulled the hose off supplying water to the freshwater exchanger and blew air into it, and declared it almost plugged. He then grabbed a bottle of mild oxalic acid solution , held the hose straight up and poured the solution in, counted to 10, then flushed it out with water. Not something I would have the nerve to do myself! You may want to check your thermostat first to ensure it''s working properly.

Fessalo 10-25-2011 07:40 AM

I would definitely check the heat exchanger intake tube. Beta Marine suggested this to me after I experienced the same thing and sure enough it was half plugged with small debri and remnants of anode and you cannot detect this by the amount of water coming's just that the water coming in basically goes straight out without circulating efficiently where it should.

JimsCAL 10-25-2011 11:49 AM

Is this engine raw water or fresh water cooled? Sounds like blockage in the raw water system, which could mean the engine (if raw water cooled) or the heat exchanger (if fresh water cooled). Is a strainer installed in the inlet? If not, you could have debris blocking the passages. A backflush with fresh water may help if that's the case. If the engine is raw water cooled, you could have scaling and then you may need a flush with Rydlyme Marine or oxalic acid.

Tim R. 10-25-2011 11:54 AM

Thread is over 8 years old. hopefully solved by now.

Seaduction 10-25-2011 12:56 PM


Originally Posted by treilley (Post 790095)
Thread is over 8 years old. hopefully solved by now.

Good Point!!;)

JimsCAL 10-25-2011 05:28 PM

Ah well. Fooled again!!

Capt Len 10-29-2011 03:35 PM

Good advice doesn't improve with age but neither does it deteriorate.I find these old threads a good read.

All times are GMT -4. The time now is 07:06 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome